battery questions

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From: Geoff Ruth (gruth@leadershiphigh.org)
Date: Wed May 22 2002 - 19:37:17 PDT 

Message-Id: <a05010400b91205372adc@[192.168.1.25]>
Date: Wed, 22 May 2002 19:37:17 -0700
From: Geoff Ruth <gruth@leadershiphigh.org>
Subject: battery questions

One of my brilliant students came up with some questions that I don't
understand.

If you directly connect the terminals of a battery with a wire, it
will start to shortcircuit and heat up. Why, though, doesn't the
battery immediately discharge when it's shortcircuited? Is it because
the wire has a resistance and therefore can only carry a certain
amount of amperage at once?

Here's another question: if you hook up a battery to a small
lightbulb, it can power the lightbulb for hours, until the battery
runs dead. Why doesn't the battery immediately "try" to discharge in
a massive burst of current, and burn out either the wires or the
lightbulb filament?

In other words, it seems like something is controlling the rate of
discharge of the battery.

Both these questions came up through studying electrochemistry, not
through the physics side of e/m.

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